Brown’s executive order came the same day he signed into law a bill mandating California get 100 percent of its electricity from renewables and “zero-carbon” energy sources. Brown is also preparing to host a global warming activist summit Wednesday.

“California is committed to doing whatever is necessary to meet the existential threat of climate change,” Brown said Monday. “But have no illusions, California and the rest of the world have miles to go before we achieve zero-carbon emissions.”

Brown is right in one sense. California does have “miles to go” to meet Brown’s executive order because it relies on “magical thinking” and “science fiction,” according to experts.

Existing executive orders call for California to cut greenhouse gas emissions 80 percent below 1990 levels by 2050, and state law requires emissions to be cut 40 percent by 2030. However, that’s not enough to meet the goals of the Paris climate accord, according to United Nations models.

What Brown ordered is not just reducing emissions, but instead implied sucking more greenhouse gas out of the air than human activities in his state put up — and not just for electricity. Brown’s order applies to the entire economy, including transportation and agriculture.

So what does negative emissions mean in practice? Well, no one really knows, but experts have put forward ideas to suck carbon dioxide from the atmosphere.

Scientists have also proposed technologies to literally suck carbon dioxide from the air and store it underground or in the ocean. Experts have also suggested reforestation, ocean fertilization and what’s known as enhanced weathering.

Enhanced weathering is the rather hilarious idea that one can use rocks to, in effect, store CO2 emissions. In theory, the rocks would react with CO2 and water to form an alkaline solution that leaks into the ocean.

However, all of these proposals remains “magical thinking” at this point, according to an editorial in the journal Nature.

Enhanced weathering, for example, would require “an area about the size of Texas … of US agricultural land every year” just to “soak up 13% of the annual global emissions from agriculture,” according to Nature.

Another proposed technology that’s cited by the IPCC is bioenergy with carbon capture and storage (BECCS). This is basically removing CO2 through growing plants, which are then burned for energy. The emissions are then captured and stored underground.

Of course, BECCS is another magical solution that’s baked into the IPCC’s models of what needs to be done to limit future global warming to 2 degrees Celsius.

University of Colorado professor Roger Pielke, Jr. recently published a paper on the problems with the UN’s use of BECCS to sell the Paris climate accord.

“Carbon dioxide removal at massive scale is science fiction — like a light saber, incredible but not real,” Pielke wrote.

“Yet BECCS plays a very real role in today’s climate policy arena,” Pielke wrote, “by helping to maintain the climate policy envelope and save us from having to do the enormously difficult and uncomfortable work of thinking how we might go about addressing accumulating carbon dioxide in the atmosphere differently than we have since the 1980s and ’90s.”

“If nothing else, full implementation of BECCS ‘at scale’ would require the use of a global land area one and a half times the size of India,” Pielke wrote about the staggering environmental cost of “negative emissions” technology.

Indeed, the European Academies Science Advisory Council concluded in early 2018 that negative emissions technologies “offer only limited realistic potential to remove carbon from the atmosphere and not at the scale envisaged in some climate scenarios.”

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